Casterboard



FIG. 1 is a front view thereof;

FIG. 2 is a left elevation view thereof;

FIG. 3 is a perspective view thereof;

FIG. 4 is a right elevation view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a back view thereof; and,

FIG. 7 is a perspective back view thereof.

The broken lines represent portions of the article that form no part of the claim. 

CLAIM The ornamental design for a casterboard, as shown and described. 